The present invention relates to a gravity actuated stop for use with a crane component, such as a boom stop used on a mobile lifting crane, and more particularly to stop having a gravity actuated mechanism requiring no user intervention or external power source.
Lift cranes typically include a carbody; ground engaging members elevating the carbody off the ground; a rotating bed rotatably connected to the carbody such that the rotating bed can swing with respect to the ground engaging members; and a boom pivotally mounted on the rotating bed, with a load hoist line extending there from. For mobile lift cranes, the ground engaging members are moveable ground engaging members. There are different types of moveable ground engaging members, most notably tires for truck mounted cranes, and crawlers. Typically the mobile lift cranes include a counterweight to help balance the crane when the crane lifts a load.
A crane with a pivotable boom will typically include at least one stop member, such as a boom stop, which is used to prevent a crane component from inadvertently moving into a particular orientation. For example, a boom stop may prevent a boom from rotating into a near vertical orientation and a jib stop may similarly prevent a jib from rotating to a near vertical position. The stops provide an extra layer of safety when the crane is in operation, but may not be necessary when the crane is not loaded. Moreover, the stops may actually be a hindrance when assembling a crane, as they may prevent movement necessary for assembly.
Currently, it is common practice to assemble a crane with at least one stop disabled. For example, when a boom and a jib are connected, the boom is typically positioned near the ground and the jib is positioned in-line with the boom. Once the boom and the jib are connected, the boom may be raised lifting the jib. The jib may then be angled down, and a stop may be installed to prevent the jib from extending in line with the boom. If the jib were to extending in line with the boom, it may damage the jib, tip the crane, or damage the boom. The jib stop provides a backup safety measure to ensure the jib does not extend in line with the boom during operation.